Avulsion cycles and their stratigraphic signature on an experimental backwater‐controlled delta

River deltas grow in large part through repeated cycles of lobe construction and channel avulsion. Understanding avulsion cycles is important for coastal restoration and ecology, land management, and flood hazard mitigation. Emerging theories suggest that river avulsions on lowland deltas are controlled by backwater hydrodynamics; however, our knowledge of backwater-controlled avulsion cycles is limited. Here, we present results from an experimental delta that evolved under persistent backwater hydrodynamics achieved through variable flood discharges, shallow bed-slopes, and subcritical flows. The experimental avulsion cycles consisted of an initial phase of avulsion setup, an avulsion trigger, selection of a new flow path, and abandonment of the parent channel. Avulsions were triggered during the largest floods (78% of avulsions) after the channel was filled by a fraction (0.3 ± 0.13) of its characteristic flow depth at the avulsion site, which occurred in the upstream part of the backwater zone. The new flow path following avulsion was consistently one of the shortest paths to the shoreline, and channel abandonment occurred through temporal decline in water flow and sediment delivery to the parent channel. Experimental synthetic stratigraphy indicates that the bed thicknesses were maximum at the avulsion sites, consistent with our morphologic measurements of avulsion setup and the idea that there is a record of avulsion locations and thresholds in sedimentary rocks. Finally, we discuss the implications of our findings within the context of sustainable management of deltas, their stratigraphic record, and predicting avulsions on deltas

A multi-gene signature predicts outcome in patients with pancreatic ductal adenocarcinoma.

© 2014 Haider et al.; licensee BioMed Central. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Improved usage of the repertoires of pancreatic ductal adenocarcinoma (PDAC) profiles is crucially needed to guide the development of predictive and prognostic tools that could inform the selection of treatment options

Screaming 'Black' Murder: Crime Fiction and the Construction of Ethnic Identities

A significant segment of crime fiction is concerned with the representation of ethnic identities and may to some extent be considered paradigmatic of the participation of literary texts in discourses on race and minorities. This article explores constructions of ethnic identities in American, British, and South African crime fiction from the 1920s to the early twenty-first century. In particular, the focus will be on such texts in which the ethno-cultural identity of the detective gives special prominence not only to the ethnic particularity of the fictional character itself and of its environs but frequently also to that of its author. Main texts discussed are Rudolph Fisher’s The Conjure Man Dies (1932), Earl Derr Biggers’ The House Without a Key (1925) and The Black Camel (1929), Walter Mosley’s Devil in a Blue Dress (1990) and Little Scarlet (2004) as well as James McClure’s The Gooseberry Fool (1974) and Patrick Neate’s City of Tiny Lights (2005). It is argued that all of these texts have a distinct subversive potential of which the construction of ethnic identities becomes the main vehicle because these identities are the products and the catalysts of the conflicts negotiated in ethnic crime fiction and correlating to ‘reality’

The genetic architecture of the human cerebral cortex

The cerebral cortex underlies our complex cognitive capabilities, yet little is known about the specific genetic loci that influence human cortical structure. To identify genetic variants that affect cortical structure, we conducted a genome-wide association meta-analysis of brain magnetic resonance imaging data from 51,665 individuals. We analyzed the surface area and average thickness of the whole cortex and 34 regions with known functional specializations. We identified 199 significant loci and found significant enrichment for loci influencing total surface area within regulatory elements that are active during prenatal cortical development, supporting the radial unit hypothesis. Loci that affect regional surface area cluster near genes in Wnt signaling pathways, which influence progenitor expansion and areal identity. Variation in cortical structure is genetically correlated with cognitive function, Parkinson's disease, insomnia, depression, neuroticism, and attention deficit hyperactivity disorder

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference